Abstract 1648: Primary myeloma plasma cells are capable of growth in adult, normal whole human bone marrow environment .

Abstract

Abstract Multiple myeloma (MM) is a neoplasm of low proliferative plasma cells that are highly dependent on bone marrow (BM) microenvironment for survival and growth. Primary human MM cells do not survive in conditions designed for cell lines and cell lines do not represent the primary cell heterogeneity and are microenvironment independent. Current in vitro and in vivo systems for primary human MM are limited to co-culture with specific BM cell type or growth in immunodeficient animal model. We and others have demonstrated the ability of the recognizable mature, C138+ or CD45-/CD38+ MM cells to produce MM in those experimental systems. The aim of the study was to establish and test the survival and growth of primary MM plasma cells in long term culture with a complete adult normal BM. This system is different from the autologous BM culture that is already affected by the disease. Whole BM cells from healthy donors were cultured in αMEM medium supplemented with 10% FBS and 10% serum from MM patients. Following 7-9 days the cultures were composed of adherent and nonadherent cellular compartments. The nonadherent compartment contained typical BM hematopoietic cells such monocytes, B and T lymphocytes and NK cells as assessed by flow cytometry, while the adherent compartment contained cells that morphologically resemble macrophages, osteoclasts, megakaryocytes and fibroblast-like cells. At this culture stage, CD138-selected MM cells from 13 patients were added to the BM cultures and survival and growth of MM cells were determined after 7 days by assessing proportion of CD45low/intermediate/CD38high MM plasma cells among total number of nonadherent cells. Low proportions of normal plasma cells (0.1-1.7%) were also detected in the cultures throughout the duration of experiments. In additional study, we used luciferase-expressing IL6-dependent INA6 MM cells and stroma-dependent MM line to assess MM growth within the whole BM cultures using bioluminescence analysis. Cell viability was constantly high (>90%) in the primary MM cell-normal BM cultures. Subsets of primary MM plasma cells were survived and detected in all culture cases while in 9 of 13 experiments, number of primary MM plasma cells was heterogeneously increased by 63±19% (p<0.01). INA6 and stroma-dependent line had growth advantage in this culture compared to their standard growth conditions with IL6 or stromal cells, respectively. Patient serum but not healthy donor serum was essential for establishing primary MM growth. This culture system demonstrates the ability of MM plasma cells to grow in a normal, adult whole human BM microenvironment and is appropriate for studying MM-microenvironment interaction, characterization of MM cell subpopulations capable of long term survival and targeted therapy. Citation Format: Rakesh Bam, Sathisha Upparahalli Venkateshaiah, Xin Li, Sharmin Khan, Wen Ling, Bart Barlogie, Joshua Epstein, Shmuel Yaccoby. Primary myeloma plasma cells are capable of growth in adult, normal whole human bone marrow environment . [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1648. doi:10.1158/1538-7445.AM2013-1648